Files
lcdproc/server/drivers/CFontz633io.c
T
2005-07-27 19:31:08 +00:00

562 lines
17 KiB
C

/* This file should be release under the GPL,
* However most of this is translation from the windows code
* from Brent A. Crosby.
* So I have to check with him.
*/
/*
* ===========================================================================
* 633 Test code for linux.
* Copyright 2002, David GLAUDE
* Partial copyright
* 2001 Crystalfontz America, Inc.
* brent@crystalfontz.com
* Written by Brent A. Crosby
* www.crystalfontz.com
* ===========================================================================
*/
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include "config.h"
#if defined(HAVE_SYS_SELECT_H)
# include <sys/select.h>
#else
# include <sys/time.h>
# include <sys/types.h>
#endif /* defined(HAVE_SYS_SELECT_H) */
#include "CFontz633io.h"
#define TRY_AGAIN 0
#define GOOD_MSG 1
#define GIVE_UP 2
/* static local functions */
static void send_packet(int fd, COMMAND_PACKET *out);
static int get_crc(char *buf, int len, int seed);
static int test_packet(int fd, unsigned char response);
static void treat_packet(void);
static int check_for_packet(int fd, unsigned char expected_length);
static void print_packet(COMMAND_PACKET *packet);
/* local variables */
static COMMAND_PACKET incoming_command;
/* global variables */
KeyRing keyring;
ReceiveBuffer receivebuffer;
/*
* KeyRing handling functions.
* This separates the producer from the consumer.
* It is just a small fifo of unsigned char.
*/
/** initialize/empty key ring by resetting its read & write pointers */
void EmptyKeyRing(KeyRing *kr)
{
kr->head = kr->tail = 0;
}
/** add byte to key ring; return success (byte added) / failure (key ring is full) */
int AddKeyToKeyRing(KeyRing *kr, unsigned char key)
{
if (((kr->head + 1) % KEYRINGSIZE) != (kr->tail % KEYRINGSIZE)) {
/* fprintf(stderr, "We add key: %d\n", key); */
kr->contents[kr->head % KEYRINGSIZE] = key;
kr->head = (kr->head + 1) % KEYRINGSIZE;
return 1;
}
/* KeyRing overflow: do not accept extra key */
return 0;
}
/** get byte from key ring (or '\0' if key ring is empty) */
unsigned char GetKeyFromKeyRing(KeyRing *kr)
{
unsigned char retval = '\0';
kr->tail %= KEYRINGSIZE;
if ((kr->head % KEYRINGSIZE) != kr->tail) {
retval = kr->contents[kr->tail];
kr->tail = (kr->tail + 1) % KEYRINGSIZE;
}
/* if (retval) fprintf(stderr, "We remove key: %d\n", retval); */
return retval;
}
/** send message with arguments to the given handle */
void send_bytes_message(int fd, unsigned char msg, int len, unsigned char *data)
{
COMMAND_PACKET out;
out.command = msg;
out.data_length = (unsigned char) ((len > MAX_DATA_LENGTH) ? MAX_DATA_LENGTH : len);
memcpy(out.data, data, out.data_length);
/* send message & calc CRC */
send_packet(fd, &out);
}
/** send message with one byte argument to the given handle */
void send_onebyte_message(int fd, unsigned char msg, unsigned char value)
{
COMMAND_PACKET out;
out.command = msg;
out.data_length = 1;
out.data[0] = value;
/* send message & calc CRC */
send_packet(fd, &out);
}
/** send message without data to the given handle */
void send_zerobyte_message(int fd, unsigned char msg)
{
COMMAND_PACKET out;
out.command = msg;
out.data_length = 0;
/* send message & calc CRC */
send_packet(fd, &out);
}
/** send out to the given handle; calc & send CRC when doing so */
static void
send_packet(int fd, COMMAND_PACKET *out)
{
write(fd, &out->command, 1);
write(fd, &out->data_length, 1);
if (out->data_length > 0)
write(fd, out->data, out->data_length);
/* calculate & send the CRC */
out->crc.as_word = get_crc((unsigned char *) out, out->data_length + 2, 0xFFFF);
write(fd, out->crc.as_bytes, 2);
/**** TEST STUFF ****/
// print_packet(out);
/* Every time we send a message, we also check for an incoming one. */
test_packet(fd, 0x40 | out->command);
}
/** calculate CRC over given buffer with given length */
/* According to the "Painless Guide to CRC error dectectin algorithmsi
* (http://www.repairfaq.org/filipg/LINK/F_crc_v3.html) this is the table driven
* implementation of a CRC with the following parameters:
* - WIDTH: 16 (16 bit CRC)
* - POLY: 0x1021 (generating polynomial)
* - INIT: 0xFFFF (seed value for the register when starting the algorithm)
* - REFIN: TRUE (reflect [i.e. bit-swap] each input byte before being processed)
* - REFOUT: TRUE (reflect [i.e. bit-swap] the result before the XOROUT phase)
* - XOROUT: 0xFFFF (value to xor the result before returning it as crc)
*/
static int
get_crc(char *buf, int len, int seed)
{
/* CRC lookup table to avoid bit-shifting loops. */
static const word crcLookupTable[256] = {
0x00000, 0x01189, 0x02312, 0x0329B, 0x04624, 0x057AD, 0x06536, 0x074BF,
0x08C48, 0x09DC1, 0x0AF5A, 0x0BED3, 0x0CA6C, 0x0DBE5, 0x0E97E, 0x0F8F7,
0x01081, 0x00108, 0x03393, 0x0221A, 0x056A5, 0x0472C, 0x075B7, 0x0643E,
0x09CC9, 0x08D40, 0x0BFDB, 0x0AE52, 0x0DAED, 0x0CB64, 0x0F9FF, 0x0E876,
0x02102, 0x0308B, 0x00210, 0x01399, 0x06726, 0x076AF, 0x04434, 0x055BD,
0x0AD4A, 0x0BCC3, 0x08E58, 0x09FD1, 0x0EB6E, 0x0FAE7, 0x0C87C, 0x0D9F5,
0x03183, 0x0200A, 0x01291, 0x00318, 0x077A7, 0x0662E, 0x054B5, 0x0453C,
0x0BDCB, 0x0AC42, 0x09ED9, 0x08F50, 0x0FBEF, 0x0EA66, 0x0D8FD, 0x0C974,
0x04204, 0x0538D, 0x06116, 0x0709F, 0x00420, 0x015A9, 0x02732, 0x036BB,
0x0CE4C, 0x0DFC5, 0x0ED5E, 0x0FCD7, 0x08868, 0x099E1, 0x0AB7A, 0x0BAF3,
0x05285, 0x0430C, 0x07197, 0x0601E, 0x014A1, 0x00528, 0x037B3, 0x0263A,
0x0DECD, 0x0CF44, 0x0FDDF, 0x0EC56, 0x098E9, 0x08960, 0x0BBFB, 0x0AA72,
0x06306, 0x0728F, 0x04014, 0x0519D, 0x02522, 0x034AB, 0x00630, 0x017B9,
0x0EF4E, 0x0FEC7, 0x0CC5C, 0x0DDD5, 0x0A96A, 0x0B8E3, 0x08A78, 0x09BF1,
0x07387, 0x0620E, 0x05095, 0x0411C, 0x035A3, 0x0242A, 0x016B1, 0x00738,
0x0FFCF, 0x0EE46, 0x0DCDD, 0x0CD54, 0x0B9EB, 0x0A862, 0x09AF9, 0x08B70,
0x08408, 0x09581, 0x0A71A, 0x0B693, 0x0C22C, 0x0D3A5, 0x0E13E, 0x0F0B7,
0x00840, 0x019C9, 0x02B52, 0x03ADB, 0x04E64, 0x05FED, 0x06D76, 0x07CFF,
0x09489, 0x08500, 0x0B79B, 0x0A612, 0x0D2AD, 0x0C324, 0x0F1BF, 0x0E036,
0x018C1, 0x00948, 0x03BD3, 0x02A5A, 0x05EE5, 0x04F6C, 0x07DF7, 0x06C7E,
0x0A50A, 0x0B483, 0x08618, 0x09791, 0x0E32E, 0x0F2A7, 0x0C03C, 0x0D1B5,
0x02942, 0x038CB, 0x00A50, 0x01BD9, 0x06F66, 0x07EEF, 0x04C74, 0x05DFD,
0x0B58B, 0x0A402, 0x09699, 0x08710, 0x0F3AF, 0x0E226, 0x0D0BD, 0x0C134,
0x039C3, 0x0284A, 0x01AD1, 0x00B58, 0x07FE7, 0x06E6E, 0x05CF5, 0x04D7C,
0x0C60C, 0x0D785, 0x0E51E, 0x0F497, 0x08028, 0x091A1, 0x0A33A, 0x0B2B3,
0x04A44, 0x05BCD, 0x06956, 0x078DF, 0x00C60, 0x01DE9, 0x02F72, 0x03EFB,
0x0D68D, 0x0C704, 0x0F59F, 0x0E416, 0x090A9, 0x08120, 0x0B3BB, 0x0A232,
0x05AC5, 0x04B4C, 0x079D7, 0x0685E, 0x01CE1, 0x00D68, 0x03FF3, 0x02E7A,
0x0E70E, 0x0F687, 0x0C41C, 0x0D595, 0x0A12A, 0x0B0A3, 0x08238, 0x093B1,
0x06B46, 0x07ACF, 0x04854, 0x059DD, 0x02D62, 0x03CEB, 0x00E70, 0x01FF9,
0x0F78F, 0x0E606, 0x0D49D, 0x0C514, 0x0B1AB, 0x0A022, 0x092B9, 0x08330,
0x07BC7, 0x06A4E, 0x058D5, 0x0495C, 0x03DE3, 0x02C6A, 0x01EF1, 0x00F78
};
/* initialize the new crc with the given seed */
int newCrc = seed;
/* This algorithm is based on the IrDA LAP example */
while (len-- > 0)
newCrc = (newCrc >> 8) ^ crcLookupTable[(newCrc ^ *buf++) & 0xFF];
/* Make this crc match the one's complement that is sent in the packet */
return ((~newCrc) & 0xFFFF);
}
/*============================================================================
* 635 WinTest Code.
* Copyright 2001, Crystalfontz America, Inc. Written by Brent A. Crosby
* www.crystalfontz.com, brent@crystalfontz.com
*============================================================================
*/
/*---------------------------------------------------------------------------*/
/* This is some code that kind of makes the windows stuff look a little
* like the DOS/633 interrupt driven serial stuff. Basically there is a
* circular buffer, and SyncReceiveBuffer() uses ReadFile() to put data
* into the circular buffer much like the DOS stuff uses an ISR to put
* the data into the buffer. Then the rest of the functions work like
* the counterparts in the 633,
*/
/* v TailPeek */
/* -------------------------------------------------- */
/* ^ Tail ^ Head */
/** initialize/empty receive buffer by resetting its pointers */
void EmptyReceiveBuffer(ReceiveBuffer *rb)
{
rb->head = rb->tail = rb->peek = 0;
}
/** read given number of bytes from given file handle into receive buffer */
void SyncReceiveBuffer(ReceiveBuffer *rb, int fd, unsigned int number)
{
unsigned char buffer[MAX_DATA_LENGTH];
int BytesRead;
#if defined(HAVE_SELECT) && defined(CFONTZ633_WRITE_DELAY) && (CFONTZ633_WRITE_DELAY > 0)
fd_set rfds;
struct timeval timeout;
int retval;
FD_ZERO(&rfds);
FD_SET(fd, &rfds);
timeout.tv_sec = 0;
timeout.tv_usec = CFONTZ633_WRITE_DELAY;
retval = select(fd + 1, &rfds, NULL, NULL, &timeout);
if (!retval)
return;
#endif /* defined(HAVE_SELECT) && defined(CFONTZ633_WRITE_DELAY) && (CFONTZ633_WRITE_DELAY > 0) */
if (number > MAX_DATA_LENGTH)
number = MAX_DATA_LENGTH;
BytesRead = read(fd, buffer, number);
if (BytesRead == -1) {
/* fprintf(stderr, "~~~Problem reading: %s .\n", strerror(errno)); */
}
else {
int i;
/* fprintf(stderr, "Read %d Bytes:", BytesRead); */
/* wrap write pointer to the receive buffer */
rb->head %= RECEIVEBUFFERSIZE;
/* store the bytes read */
for (i = 0; i < BytesRead; i++) {
/* fprintf(stderr, " %02x", buffer[i]); */
rb->contents[rb->head] = buffer[i];
/* increment write pointer (wrap if needed) */
rb->head = (rb->head + 1) % RECEIVEBUFFERSIZE;
}
/* fprintf(stderr, "\n"); */
}
}
/** return number of bytes available for reading in receive buffer */
int BytesAvail(ReceiveBuffer *rb)
{
int avail_bytes = rb->head - rb->tail;
if (avail_bytes < 0)
avail_bytes += RECEIVEBUFFERSIZE;
return(avail_bytes % RECEIVEBUFFERSIZE);
}
/** get next byte from receive buffer (return '\0' if buffer is empty) */
unsigned char GetByte(ReceiveBuffer *rb)
{
unsigned char return_byte = '\0';
/* wrap read pointer to the receive buffer */
rb->tail %= RECEIVEBUFFERSIZE;
/* See if there are any more bytes available. */
if (rb->tail != (rb->head % RECEIVEBUFFERSIZE)) {
/* There is at least one more byte. */
return_byte = rb->contents[rb->tail];
/* Increment read pointer (wrap if needed) */
rb->tail = (rb->tail + 1) % RECEIVEBUFFERSIZE;
}
return(return_byte);
}
/** return number of bytes available for peeking in receive buffer */
int PeekBytesAvail(ReceiveBuffer *rb)
{
int avail_bytes = rb->head - rb->peek;
if (avail_bytes < 0)
avail_bytes += RECEIVEBUFFERSIZE;
return(avail_bytes % RECEIVEBUFFERSIZE);
}
/** sync peek pointer with read pointer */
void SyncPeekPointer(ReceiveBuffer *rb)
{
rb->peek = rb->tail;
}
/** accept ppeked data by syncing the read pointer to the peek pointer */
void AcceptPeekedData(ReceiveBuffer *rb)
{
rb->tail = rb->peek;
}
/** peek next byte from receive buffer (return '\0' if buffer is empty) */
unsigned char PeekByte(ReceiveBuffer *rb)
{
unsigned char return_byte = '\0';
/* wrap peek pointer to the receive buffer */
rb->peek %= RECEIVEBUFFERSIZE;
/* See if there are any more bytes available. */
if (rb->peek != (rb->head % RECEIVEBUFFERSIZE)) {
/* There is at least one more byte. */
return_byte = rb->contents[rb->peek];
/* Increment the peek pointer (wrap if needed). */
rb->peek = (rb->peek + 1) % RECEIVEBUFFERSIZE;
}
return(return_byte);
}
/* I should use the value GIVE_UP and not reenter if there is no extra
* byte read from the serial port
*/
static int
test_packet(int fd, unsigned char response)
{
int is_msg;
#if defined(HAVE_SELECT) && defined(CFONTZ633_WRITE_DELAY) && (CFONTZ633_WRITE_DELAY > 0)
int response_received = 0;
while (!response_received) {
is_msg = check_for_packet(fd, MAX_DATA_LENGTH);
while (is_msg != GIVE_UP) {
if (is_msg == GOOD_MSG) {
treat_packet();
// do we need treat_packet as separate function ?
if (incoming_command.command == response)
response_received = 1;
}
is_msg = check_for_packet(fd, MAX_DATA_LENGTH);
}
}
#else
is_msg = check_for_packet(fd, MAX_DATA_LENGTH);
while (is_msg != GIVE_UP) {
if (is_msg == GOOD_MSG)
treat_packet();
is_msg = check_for_packet(fd, MAX_DATA_LENGTH);
}
#endif /* defined(HAVE_SELECT) && defined(CFONTZ633_WRITE_DELAY) && (CFONTZ633_WRITE_DELAY > 0) */
return 1;
}
static void
treat_packet(void)
{
if (incoming_command.command == 0x80) {
AddKeyToKeyRing(&keyring, incoming_command.data[0]);
}
}
/*============================================================================
* check_for_packet()
*
* check_for_packet() will see if there is a valid packet in the input buffer.
* If there is, it will copy it into incoming_command and return 1. If there
* is not it will return 0. incoming_packet may get partially filled with
* garbage if there is not a valid packet available.
*----------------------------------------------------------------------------
*/
/* Let's return
* O if we have no message but we should try again immediatly
* 1 if we have a message correctly identified
* 2 if we have no message and we should not retry until new input
* So a loop should run as long as we have no 0
* If we have a 2 we should avoid comming back there.
*/
static int
check_for_packet(int fd, unsigned char expected_length)
{
int i;
int testcrc;
SyncReceiveBuffer(&receivebuffer, fd, expected_length);
//First off, there must be at least 4 bytes available in the input stream
//for there to be a valid command in it (command, length, no data, CRC).
if (BytesAvail(&receivebuffer) < 4) {
/* fprintf(stderr, "Not enough bytes available for even the smallest message.\n"); */
return(GIVE_UP); /* We don't need to retry before more byte are received */
}
/* Look into the buffer without removing the data. */
SyncPeekPointer(&receivebuffer);
/* look at potential command byte */
incoming_command.command = PeekByte(&receivebuffer);
/* Only commands 0 through MAX_COMMAND are valid */
if (MAX_COMMAND < (0x3F & incoming_command.command)) {
/* Throw out one byte of garbage. Next pass through should re-sync. */
GetByte(&receivebuffer);
/* fprintf(stderr, "###: Unknown command.\n"); */
return(TRY_AGAIN);
}
/* There is a valid command byte. Get the data_length. */
incoming_command.data_length = PeekByte(&receivebuffer);
/* The data length must be within reason. */
if (MAX_DATA_LENGTH < incoming_command.data_length) {
//Throw out one byte of garbage. Next pass through should re-sync.
GetByte(&receivebuffer);
/* fprintf(stderr, "###: Too long packet: %d.\n", incoming_command.data_length); */
return(TRY_AGAIN);
}
// Now there must be at least incoming_command.data_length + sizeof(CRC) bytes
// still available for us to continue.
if ((int) PeekBytesAvail(&receivebuffer) < (incoming_command.data_length + 2)) {
//It looked like a valid start of a packet, but it does not look
//like the complete packet has been received yet.
/* fprintf(stderr, "Not enough read to check the complete message.\n"); */
return(GIVE_UP); /* Let's not return until more byte are available */
}
/* There is enough data to make a packet. Transfer over the data. */
for (i = 0; i < incoming_command.data_length; i++)
incoming_command.data[i] = PeekByte(&receivebuffer);
//Now move over the CRC.
incoming_command.crc.as_bytes[0] = PeekByte(&receivebuffer);
incoming_command.crc.as_bytes[1] = PeekByte(&receivebuffer);
//Now check the CRC.
//Compute the expected CheckSum
testcrc = get_crc((unsigned char *) &incoming_command,
incoming_command.data_length+2, 0xFFFF);
if (incoming_command.crc.as_word == testcrc) {
//This is a good packet. I'll be horn swaggled. Remove the packet
//from the serial buffer.
AcceptPeekedData(&receivebuffer);
//Let our caller know that incoming_command has good stuff in it.
/* print_packet(&outgoing_response); */
return(GOOD_MSG);
}
/* The CRC did not match. Toss out one byte of garbage.
* Next pass through should re-sync.
*/
GetByte(&receivebuffer);
/* fprintf(stderr, "###: Wrong CheckSum. computed/real %04x:%04x \n",
testcrc, incoming_command.crc.as_word); */
return(TRY_AGAIN);
}
/*
* This is a debugging function.
* It should be removed or compiled in conditionally.
* Currently it is still using printf for debugging.
*/
static void
print_packet(COMMAND_PACKET *packet)
{
int i, cmd, top, len;
top = (0xC0 & (packet->command)) >> 6;
cmd = (0x3F & (packet->command));
len = packet->data_length;
fprintf(stderr, "Message (%d,%d) %d [", top, cmd, len);
//There is enough data to make a packet. Transfer over the data.
for (i = 0; i < packet->data_length; i++)
fprintf(stderr, " %02x", packet->data[i]);
fprintf(stderr, " ] %02x %02x .\n", packet->crc.as_bytes[0], packet->crc.as_bytes[1]);
}